SEC Commissioner Mike Slive says high salaries for football coaches are part of the free-market system. / John David Mercer, USA TODAY Sports

by George Schroeder, USA TODAY Sports

by George Schroeder, USA TODAY Sports

BIRMINGHAM, Ala. â?? As college football coaches' salaries continue to skyrocket, so does the pressure to perform. Nowhere is that relationship better illustrated than in the Southeastern Conference.

SEC football teams have won six consecutive Bowl Championship Series national championships, and No. 2 Alabama will play for the crystal football again Jan. 7 against top-ranked Notre Dame. But four of the league's 14 head-coaching jobs turned over in the past few weeks â?? including Auburn's Gene Chizik, less than two years after winning a national title. Correlation?

"I'm not sure winning the national championship is the driver," SEC Commissioner Mike Slive said Wednesday, referring to the recent firings and noting that the pressure to win big has heightened in other conferences, too. "I think it's a question of whether or not institutions feel they are able to compete successfully in this conference, or any conference."

Led by Nick Saban's $5.5 million annual salary, the SEC has four of the top 10 highest-paid head coaches, according to a USA TODAY Sports analysis of coaching contracts and other documents. The league's assistant coaches have cashed in, too: Six of the top 15 highest-paid staffs hail from the SEC, with LSU's assistants making more than $4 million combined. USA TODAY Sports also published a survey of assistant coaches salaries this week.

Arkansas' opening came about when Bobby Petrino, who had been highly successful, got into trouble off the field. But Tennessee and Kentucky parted ways with Derek Dooley and Joker Phillips, respectively, because the coaches didn't win enough. Auburn fired Chizik as the Tigers went 3-9 overall and 0-8 in the SEC.

"It's a very competitive business," Slive said. "I think coaches go into it now, their eyes are open, the expectations are high, and all of our schools want to be competitive."

Slive declined to say whether coaches are being paid too much. The average salary for Football Bowl Subdivision-level head coaches increased nearly 12% over last year, to $1.64 million, and more than 70% since 2006, when USA TODAY Sports began tracking compensation. The average assistant coach makes almost $201,000.

"We live in a free-market system," Slive said. "That prohibits any legal restraints on salaries, or for any organization to put any restrictions. So it's really a matter of institutions making decisions based upon their own economic realities."